For most of us, there is nothing more satisfying nor energising than a good cuppa or an afternoon kip.
Caffeine (most commonly consumed in the form of a steaming coffee) and napping are both proven keys to maintaining alertness, boosting performance and, heck, sometimes just getting through the day.
But you'd never dream of putting them together, right?
Prepare to jolt awake from your sleepy, mid-morning/post-lunch abyss.
The alerting effect of caffeine takes some time to work it's way through before its action kicks in. And that is around thirty minutes after drinking.
"We know coffee has an alerting effect, and power napping can help you overcome your sleep debt. Intuitively, you would think that introducing a coffee would surely mess around your sleep, but that's not actually the case," Chin Moi Chow, Associate Professor of Sleep and Wellbeing at the University of Sydney told The Huffington Post Australia.
"The alerting effect of caffeine takes some time to work its way through before its action kicks in. And that is around 30 minutes after drinking.
Enter 'coffee naps', a genius and self-explanatory approach that involves drinking a cup of coffee before your afternoon power nap.
"A power nap is ideally about 10 to 15 minutes. If you have the nap before the alerting effect of caffeine takes place, your nap is restful and should not be disrupted as your body hasn't experienced the caffeine hit," Chow said.
How might this work?
You're still racking your brain over this one, aren't you. Let's wind it back to how the body digests and absorbs caffeine.
Caffeine acts on 'adenosine receptors', thought to be the chemicals that cause drowsiness and induce sleep.
"Caffeine acts to stop or block these receptors, meaning naturally occurring adenosine can not access them. In effect, you are less sleepy," Chow said.
Essentially, sleep clears our those chemicals and caffeine keeps them from resurfacing.
"Once you've had your coffee, the caffeine stays in your stomach before moving into your small intestine. Then it is absorbed into the bloodstream, to the brain and all parts of the body containing these receptors," Chow said.
This process takes about 45 minutes, although approximately half of it remains in the blood for 4-5 hours after drinking. This explains why upon waking from you nap, your body should feel the usual caffeine 'hit' within five to 10 minutes, and hours later.
Coffee and napping: should we have both?
The jury's still a little out on this one.
'Coffee naps' were somewhat tested by a group of researchers back in 1997. A small group of sleep-deprived people drank the equivalent of one large cup of brewed coffee before proceeding to power nap for 15 minutes.
A series of simulated drive tests later, and those who took a coffee nap appeared less likely to drift out of their lanes during a two-hour drive, compared to those who just drank coffee or decaffeinated coffee (with no nap).
Although drinking a coffee (without a nap) helped their driving performance, combining caffeine with a nap (a coffee nap) improved it even further.
The study also reported coffee naps improved the quality of the sleep during nap time, curbing dozing, rather than falling into a deep sleep. Once awake, they remained more alert for a couple of hours.
In her role as a lifestyle scientist for sleep, Chow has some questions. But she believes coffee naps can be beneficial for some -- when the timing is right. Like after lunch, with a mountain of work ahead of you.
"The combined coffee and nap equation can be useful in regards to mental performance, and it can be more powerful than a nap alone," Chow said.
"My recommendation is that coffee naps work for those who are very sleep deprived and need to say alert to power through the rest of the day. In this context, it can be quite economical.
"But they should not be taken late into the afternoon -- and they shouldn't become a habit. Like coffee drinking, if you take one too close to your normal nighttime sleep, it may interfere with how restful your sleep is."
Just make sure you're within that 30-minute window.
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